The presence of decaboxylase enzymes within the kidney permits the intrarenal conversion of amino acids to biogenic amines with potent physioligic effects. Present investigations will focus on one such enzyme-amino-acid decarboxylase. The investigations will be conducted in isolated perfused rat kidneys, anesthetized rats in vivo and chronic rat models of renal insufficiency and salt-sensitive hypertension. These techniques will be used to determine the ability of kidneys to form dopamine and and serotonin and assess their intrarenal role in the regulation of renal hemodynamics and function. Interrelationships of these renal biogenic amines with the renin-angiotensin system and prostanoids will be determined. The role of the kidney in regulating extrarenal biogenic amine formationwill be assessed. Also, it will be determined if abnormalities or renal dopamine and/or serotonin formation may play a role in salt-sensitive hypertension.